1. Field of the Invention
The weight transfer roller of the present invention relates to rollers utilized for transporting heavy loads over a weight transfer platform, such as the floor in a cargo compartment of a cargo airplane.
2. Description of the Prior Art
With the advent of modern day air transportation, the rapid transfer of heavy loads into and out of cargo planes has become an important element of efficient shipping cargo throughout the world. In recent times, it has become common practice to pre-load cargo into containers commonly referred to as cargo containers, so such containers are prepared for rapid loading onto an arriving airplane so the plane itself can have a rapid turnabout and prevent detention on the ground for slow and time consuming piecemeal loading of individual items by themselves. The loading of such cargo planes has been facilitated by installing large diameter rollers in the floor of the cargo compartments thereof with the upper surfaces thereof protruding from the floor so a flat bottom cargo container can be slid easily and rapidly thereover to be tied down in position during flight. Such rollers have commonly incorporated individual housings installed in openings formed in the floor and typically incorporate a semi-spherical basket into which the roller is nested. Interposed between the roller and the semi-spherical basket are a large number, as for instance 60 or 70, small diameter ball bearings which facilitate rolling of the large diameter roller ball on the basket during transfer of heavy loads thereover. Such prior art metallic roller balls and housings suffer the shortcoming that they are relatively heavy, thus adding tremendously to the overall weight of the airplane when a great number of such assemblies are installed and add significantly to the consumption of fuel during flight. Moreover, such prior art roller transfer assemblies, while performing satisfactorily under ideal conditions, as for instance when the underside of the cargo containers are flat and uniform thus providing for even weight distribution over an entire array of roller assemblies disposed thereunder. Some prior art assemblies attempt to provide some cushioning and vertical flexibility in location of the roller ball by use of a coil spring which creates a dangerous condition at the time of disassembly. Furthermore, such prior art devices when operating in a debris ladened environment, pick up dirt, grit and other debris in the ball bearings interposed between the roller ball and nesting basket, thus resulting in literal grinding of the ball bearings with such debris and scarring of the roller ball and eventual failure of the roller ball to roll as a load is passed thereover. A still further shortcoming of such prior art roller transfer assemblies is that when any component thereof, such as the roller ball or roller bearings has failed, the entire assembly must be discarded because of the expense of disassembly and replacement of the components.
These and other objects and advantages of the present invention will become apparent from a consideration of the following detailed description when taken in conjunction with the accompanying drawings.